Principal Problem Research Articles

Human scent samples for chemical analysis

This study is focused on finding an optimal preparation of the human scent samples for their detailed chemical analysis in connection with the possible forensic identifications of human individuals in the future. At the present time, the scent identification of people is carried out nearly exclusively using specially trained dogs. It is assumed that the human scent contains a certain group of compounds which allows the identification of people, the so-called human scent signature; however, its chemical composition is completely unknown, as of now. The principal problem of human scent studies consists in the very low concentrations of thousands of the scent compounds, whereas their relative concentrations are usually dramatically different. It seems to be obvious that the most appropriate analytical technique for these thousands of different chemical compounds is GC/MS. However, it is also necessary to find the most suitable sorbent material for human scent collection, an extraction solvent, and a pre-concentration technique. The selection of the appropriate gas chromatographic method is also important to achieve the optimal resolution of the targeted compounds. Of course, in the first instance, it is necessary to decide what it means “the most suitable” for human scent chemical analysis.

The study of the first main problem of the theory of elasticity for a layer with a cylindrical cavity

An analytic - numerical algorithm for solving a substantially spatial problem of the theory of elasticity for a layer with a longitudinal cylindrical cavity and the conditions of the first principal problem, given on the boundary surfaces, is developed.The solution is based on the generalized Fourier method applied to the Lame equation system. The cavity is considered in the cylindrical coordinate system, the layer - in Cartesian. By satisfying the boundary conditions and using special formulas for the transition between coordinate systems for basic solutions, we create infinite systems of linear algebraic equations, which are solved by the method of cutting. The numerical study of the determinant gives reason to claim that this system of equations has a single solution. As a result, stresses were obtained at different points in the elastic body.Cutting parameters were chosen so that the accuracy of the boundary conditions reaches 10-2. As the cutoff parameter increases, the accuracy of boundary conditions increases, but the duration of the calculation increases.The numerical solution of the problem is performed for a layer with a cylindrical cavity and a normal balanced load at the boundary of the layer. The analysis of the stress state gives grounds to state:1. The solution of the algebraic system of equations can be found with any degree of accuracy by the method of reduction, which is confirmed by the high accuracy of boundary conditions.2. The presence of a cavity gives rise to a redistribution of stresses, in which maximum values occur on the surface of the cavity, and tensile stresses occur at the top of the layer (which is compressed without a cavity).This method can be used in the calculation of structures, the calculation scheme of which is a layer with a cylindrical cavity, under given boundary conditions in the form of balanced stresses. Stress analysis enables the selection of geometric characteristics at the initial design stage.

Local governments and their arm’s length bodies

ABSTRACT In this paper, we discuss the state of the art on the creation of arm’s length bodies (ALBs) by local governments. We make three main contributions. First, there are many different types of ALBs and each country has its own categories; an expert survey was held identifying three common types of body, to enable future comparative research. Second, we point out that the creation of ALBs has led to a number of new challenges for local governments, particularly regarding governing bodies at arm’s length to ensure ALBs’ good performance. A lack of capacity and information have to be countered, for example, by increased monitoring – also for democratic accountability purposes. Special attention is needed for the multiple principal problem that arises when local governments jointly create ALBs. Third, research into local ALBs is still in its early stages. We present a research agenda to develop knowledge on the topic.

Energy Consumption Based Low Energy Aware Gateway (LEAG) Protocol in Wireless Sensor Networks

Wireless Sensor Networks (WSN) consists of a large amount of nodes connected in a self-directed manner. The most important problems in WSN are Energy, Routing, Security, etc., price of the sensor nodes and renovation of these networks is reasonable. The sensor node tools included a radio transceiver with an antenna and an energy source, usually a battery. WSN compute the environmental conditions such as temperature, sound, pollution levels, etc., WSN built the network with the help of nodes. A sensor community consists of many detection stations known as sensor nodes, every of which is small, light-weight and portable. Nodes are linked separately. Each node is linked into the sensors. In recent yearsWSN has grow to be an essential function in real world. The data’s are sent from end to end multiple nodes and gateways, the data’s are connected to other networks such as wireless Ethernet. MGEAR is the existing mechanism. It works with the routing and energy consumption. The principal problem of this work is choosing cluster head, and the selection is based on base station, so the manner is consumes energy. In this paper, develop the novel based hybrid protocol Low Energy Aware Gateway (LEAG). We used Zigbee techniques to reduce energy consumption and routing. Gateway is used to minimize the energy consumption and data is send to the base station. Nodes are used to transmit the data into the cluster head, it transmit the data into gateway and gateway compress and aggregate the data then sent to the base station. Simulation result shows our proposed mechanism consumes less energy, increased throughput, packet delivery ration and secure routing when compared to existing mechanism (MGEAR).

English

Hepatitis B is the principal public health problem among diverse segments of inhabitants. However, attention is not given on its prevention strategy, especially among health care workers. Hence, the intention of this study was to assess hepatitis B virus vaccination status and associated factors among health care workers working in Wolayita Sodo hospitals, Southern Ethiopia. An institution based cross-sectional study was employed from May 10 to 25, 2018. A total of 370 participants was selected using simple random sampling. A self-administered questionnaire was used and the data were entered into EpiData 3.1 and exported to SPSS 22.0 for analysis. Both bivariate and multivariable analysis were applied and statistical significance was declared at P-value < 0.05. Of the participants, 62.7% (95% CI: 57.75, 67.65) received a full dose of the vaccine. Being female (AOR=1.87, 95 % CI: 1.16, 3.01), worked for four years and above (AOR=1.91 95% CI: 1.22, 3.13], working at ward and delivery (AOR=2.26, 95% CI: 1.41, 3.63), good knowledge (AOR=2.0, 95% CI: 1.20, 3.04) and favorable attitude (AOR=1.9, 95% CI: 1.17, 2.97) were statistically associated with vaccination. This study revealed that vaccination of healthcare providers was sub-optimal. Thus, boundless stress should be given to expand the vaccination coverage of the virus. Key words: Hepatitis B virus, vaccination, healthcare workers, Ethiopia.

A multi-objective distribution-free model and method for stochastic disassembly line balancing problem

End-of-life product recycling is a hot research topic in recent years, which can reduce the waste and protect the environment. To disassemble products, the disassembly line balancing is a principal problem that selects tasks and assigns them to a number of workstations under stochastic task processing times. In existing works, stochastic task processing times are usually estimated by probability distributions or fuzzy numbers. However, in real-life applications, only their partial information is accessible. This paper studies a bi-objective stochastic disassembly line balancing problem to minimise the line design cost and the cycle time, with only the knowledge of the mean, standard deviation and upper bound of stochastic task processing times. For the problem, a bi-objective chance-constrained model is developed, which is further approximated into a bi-objective distribution-free one. Based on the problem analysis, two versions of the ϵ-constraint method are proposed to solve the transformed model. Finally, a fuzzy-logic technique is adapted to propose a preferable solution for decision makers according to their preferences. A case study is presented to illustrate the validity of the proposed models and algorithms. Experimental results on 277 benchmark-based and randomly generated instances show the efficiency of the proposed methods.

Large Shareholders’ Power and the Quality of Corporate Governance: An Analysis of Brazilian Firms

This paper analyzes the incentives of large shareholders to implement the corporate governance system that favors their interests within a framework of highly concentrated ownership and poor legal protection for investors. A metric for corporate governance based on the fulfillment of non-mandatory rules of good corporate governance is used. System GMM (Generalized Method of Moments) estimates for a balanced panel data of Brazilian firms reveal that the ownership concentration is detrimental to corporate governance quality and the quality of board composition. In accordance with the expropriation effect on principal-principal agency conflicts, by weakening the corporate governance system and board composition, large controlling shareholders may use private benefits of control. As proposed by the substitution effect, in a complementary way, controlling shareholders may renounce strong boards and directly perform management monitoring, mitigating agency conflicts with managers. Finally, the ability of large shareholders other than the main blockholder is not enough to contest his/her power to shape the corporate governance system. The work provides evidence of the prominence of the principal–principal agency problem in an emerging market, by analyzing the effect of ownership concentration over the quality of the corporate governance system, and also that other large non-controlling shareholders are not able to contest the power of the main blockholder.

A benchmark for soil organic matter degradation under variably saturated flow conditions

Soil contains the largest terrestrial pool of organic matter, and the cycling of organic carbon in soils plays a crucial role in controlling atmospheric carbon dioxide (CO2) and global climate change. Although considerable progress has been made in previous modeling studies on the fate of soil organic matter (SOM), only a few models used a process-based approach for investigating these strongly coupled and complex soil systems, which involve SOM oxidation, transient water flow, and mass transport processes in aqueous and gaseous phases. Typically, physically based models for water flow, as well as solute and gas transport, are not coupled with state-of-the-art SOM degradation models. Reactive transport models (RTMs) provide a flexible framework for implementing different SOM degradation concepts and integrating biogeochemical processes with water flow and mass transport. Given the complex nature of carbon cycling in soils coupled with flow and mass transport, code intercomparison using well-defined benchmarks is in many cases the only practical method of model verification. The benchmark presented in this manuscript focuses on SOM oxidation under variably saturated flow conditions. The benchmark consists of three problems characterized by increasing complexity. The problems were solved using two different reactive transport codes, namely HP1 and MIN3P-THCm. The first supporting problem introduces a batch-type simulation to assess kinetic networks of SOM degradation. In the second supporting problem, transient water flow, solute transport, gas generation, and diffusive gas transport are considered. The principal problem combines the kinetic networks of SOM degradation with reactive transport under variably saturated flow conditions, including CO2 transport from soils to the atmosphere. Simulation results for the benchmark problems demonstrate an overall excellent agreement between the two codes, building confidence in the ability of RTMs to simulate complex C-cycling in dynamic environments.

Large shareholders’ power and the quality of corporate governance: An analysis of Brazilian firms

This paper analyzes the incentives of large shareholders to implement the corporate governance system that favors their interests within a framework of highly concentrated ownership and poor legal protection for investors. A metric for corporate governance based on the fulfillment of non-mandatory rules of good corporate governance is used. System GMM (Generalized Method of Moments) estimates for a balanced panel data of Brazilian firms reveal that the ownership concentration is detrimental to corporate governance quality and the quality of board composition. In accordance with the expropriation effect on principal-principal agency conflicts, by weakening the corporate governance system and board composition, large controlling shareholders may use private benefits of control. As proposed by the substitution effect, in a complementary way, controlling shareholders may renounce strong boards and directly perform management monitoring, mitigating agency conflicts with managers. Finally, the ability of large shareholders other than the main blockholder is not enough to contest his/her power to shape the corporate governance system. The work provides evidence of the prominence of the principal–principal agency problem in an emerging market, by analyzing the effect of ownership concentration over the quality of the corporate governance system, and also that other large non-controlling shareholders are not able to contest the power of the main blockholder.

Subspace Selection via DR-Submodular Maximization on Lattices

The subspace selection problem seeks a subspace that maximizes an objective function under some constraint. This problem includes several important machine learning problems such as the principal component analysis and sparse dictionary selection problem. Often, these problems can be (exactly or approximately) solved using greedy algorithms. Here, we are interested in why these problems can be solved by greedy algorithms, and what classes of objective functions and constraints admit this property.In this study, we focus on the fact that the set of subspaces forms a lattice, then formulate the problems as optimization problems on lattices. Then, we introduce a new class of functions on lattices, directional DR-submodular functions, to characterize the approximability of problems. We prove that the principal component analysis, sparse dictionary selection problem, and these generalizations are monotone directional DRsubmodularity functions. We also prove the “quantum version” of the cut function is a non-monotone directional DR submodular function. Using these results, we propose new solvable feature selection problems (generalized principal component analysis and quantum maximum cut problem), and improve the approximation ratio of the sparse dictionary selection problem in certain instances.We show that, under several constraints, the directional DRsubmodular function maximization problem can be solved efficiently with provable approximation factors.

Delegating Relational Contracts to Corruptible Intermediaries

Relational contracts are typically modeled as being between a principal and an agent, such as a firm owner and a supplier. Yet, in a variety of organizations, relationships are overseen by an intermediary such as a manager. Such arrangements open the door for collusion between the manager and the agent. This paper develops a theory of such managed relational contracts. We show that managed relational contracts differ from principal-agent ones in important ways. First, kickbacks from the agent can help solve the manager's commitment problem. When commitment is difficult, this can result in higher agent effort than the principal could incentivize directly. Second, making relationships more valuable enables more collusion and hence can reduce effort. We also analyze the principal's delegation problem and show that she may or may not benefit from entrusting the relationship to a manager.

Detecting moving objects via the low-rank representation

Moving object detection is a fundamental and necessary step in many computer vision algorithms. These algorithms are built in many intelligent devices such as in the smartphones, the tachographs and the personal video recorders. Recently, the methods for performing the moving object detection based on the low-rank representation have been proposed. For these methods, it is assumed that the background is represented by a low-rank matrix. On the other hand, the foreground objects cannot be represented by low-rank matrices. They are seen as the outliers. Hence, detecting the contiguous outliers in the low-rank representation (DECELOR) can be formulated as an extension of the robust principal component analysis problem. This method fully utilizes the spatial continuity of the foreground regions. To achieve a more accurate detection, this paper integrates both the concave penalty function and the priori target rank information into a single optimization problem based on the DECELOR formulation. The optimization problem is efficiently solved by an alternating direction scheme. The computer numerical simulation results on the real-world scenes demonstrate the superiority of our method in terms of the effective handling of a wide range of complex scenarios.

Agency models based on different measures with comparison

Optimal contract regulates the expected activities of both principals and agents, and influences how the gains from the cooperation are shared between the two participators. Thus, it is necessary and wise for principals to seek for the optimal contracts during the period of negotiations. To determine the optimal contracts, there are several kinds of agency models based on different measures, such as probability measure, capacity measure, credibility measure and uncertainty measure. This paper primarily presents a comparative review of random agency model, fuzzy agency model and uncertain agency model. This comparative review is aimed at not only summarizing the structure and feature of each agency model but also guiding on how to identify the most suitable agency model for each specific principal agent problem. Motivated by this idea, these three classes of agency models are respectively investigated about their structure, feature and application, and then an empirical comparison among these models is basically carried out from several aspects, such as information diversity, decision rule and calculation. As a significant contribution, the comparative result in this paper provides the guidance for the principals on how to identify the most suitable agency model for each special principal agent problem in a certain setting.

Gasification of Municipal Solid Waste Using Tyre Char as Catalyst

Gasification is raised as the most promising technologies of municipal solid waste (MSW) removal as well as energy recovery. The principal problem related with the gasification process is the high amount of tar released during the gasification process that causes environmental and operational problems. The purpose of this study is to investigate the performance of MSW gasification using tyre char as an alternative option for catalytic gasification to produce tar free clean gas. Catalytic performance of tyre char was compared with performance of MSW gasification alone without the tyre char in a bench scale downdraft reactor. The waste tyre char removed 80% of tars in syngas at 700 °C. Analysis of the syngas compositions indicated that concentration of H2 and CO were significantly increased. Therefore, it was concluded that chars especially tyre char can be an effective and inexpensive catalyst for tar removal and syngas production of MSW gasification.

The Hermeneutics of Contemplation and World Christianity

ABSTRACT World Christianity attracts attention from a wide array of scholars, including theologians and religious studies scholars. However, do these approaches communicate with each other? Should they? Or may a hardening of disciplinary and conceptual boundaries be expected, and even preferred? The principal problem informing this article is an abiding dichotomy between theology on the one hand and religious studies approaches on the other. From our perspective, the question is whether theologically oriented research in world Christianity can be of value across the academic spectrum. Or are theological studies conceptually confined by the walls of their own normative commitments? The authors argue that maintaining an open threshold between different disciplines in the study of “other” expressions of world Christianity is important and that this may require that theologically rooted researchers adopt what the philosopher of religion D. Z. Phillips calls a “hermeneutics of contemplation.” In an important book on the subject, Phillips—addressing religious studies scholars rather than theologians—identifies theology with what he terms the “hermeneutics of recollection,” and secular theories of religion with the “hermeneutics of suspicion.” When the latter approach is shown to fall short of doing justice to religious complexity, Phillips posits the “hermeneutics of contemplation” as a more appropriate response to the religious other. We ask whether the reverse may also hold true for theologians, namely, a shift in disposition from a hermeneutics of recollection to contemplation? To ground the theoretical discussion, reference is made to research on the theme of rain rituals and prayers.

Multiple principals, multiple problems: Implications for effective governance and a research agenda for joint service delivery

The multiple principal problem refers to multiple collective action problems that organizations face when they must balance (competing) interests of multiple stakeholders under joint service delivery. It negatively affects different types of organization, yet we know little about how organizations (can) mitigate it. We expand a framework based on principal–agent theory, review the literature, and consider implications for effective governance of joint service delivery in the public sector. We observe that joint service delivery can lead to free‐riding and duplication in monitoring, lobbying by principals, and increased autonomy for agents, leading to inefficiency. We build a research agenda and tentatively suggest, based on the literature, that an interface approach, where an elected unitary actor is placed in a middle tier between politics and service delivery, might best mitigate the multiple principal problem, which is currently not dealt with effectively in public management.

A CONCEPTUAL ANALYSIS OF CORPORATE GOVERNANCE AND ITS ENFORCEMENT

Reducing agency costs is the principal problem of corporate governance. Although the scope and stringency of the laws and rules on eliminating agency costs are expanding, there is stillneed for the understanding of the supervision and enforcement of these rules. Enforcement can take the forms of public and/or private. With dispersed and concentrated ownership patterns, the relevance of public and private enforcement mechanism may differ; due to the appearance of agency problems unlikely. The purpose of this paper is to provide a conceptual analysis on corporate governance strategies involving the exercise of control rights, the appointment of independent directors, auditing, and disclosure. This paper will also include a guideline on the enforcement mechanism in Turkey and the ways in which they are used to control the agency problems; between owners and managers, controlling shareholders and non-controlling shareholders or creditors.

Scaled models for failure under impact loading

Small-scale experimentation is recognised to play an important role in the investigation of the behaviour of large-scale structures. Presently however, there exists no known procedure for analysing structures involving damage or failure by means of scaled experiments when high-rate impact loading is involved. The principal problem impeding the scaled approach is that similarity seldom exists for high-rate dissipative problems and consequently dimensional analysis provides an ineffective framework for experimental design and analysis.This paper is concerned with the application of the finite similitude theory which scales experiments by means of space distortion. Although finite similitude suffers many of the limitations of dimensional analysis it has one principal advantage, i.e. it is able to cater for inexact similitude where sources and effects of mismatch can be quantified. This feature is exploited in the work to answer the open question whether it is possible to determine the failure response of structures subjected to high rate loading by performing experimental tests on scaled structures manufactured with different materials.The efficacy of the proposed methodology for scaled experimentation is tested by means of numerical analysis on a number of well-known test cases, which are supported by experimental evidence. In particular the perforation of circular plates and the Taylor bar impacting on a rigid wall are analysed using the commercial finite element software package Abaqus. The Johnson–Cook thermo-viscoplastic constitutive equation together with the Johnson–Cook damage model are used to describe yielding, strain hardening, strain rate effects, thermal softening and material failure. It is revealed in the paper that although exact similitude is not achievable the results of the full-scale model can be predicted to good accuracy by means of scaled experimentation founded on finite similitude theory.

Phenotypes in Behçet's syndrome.

Behçet syndrome (BS) is a multi-systemic complex disorder with unknown etiology and a unique geographic distribution. It could not be possible to include it into specific classification schemes and it is certainly not a uniform disease. Several cluster and association studies revealed that it has been composed of multiple phenotypes ascribing the principal problem such as skin-mucosa, joint, eye, vascular, neurological and gastrointestinal involvement. Each phenotype has its own characteristic demographic and clinical features as such their management strategies and prognosis differ substantially. Actually, the concept of phenotyping has been well known for some time and is considered one of the basic elements of the still continuing debate whether to call this entity 'disease' or 'syndrome'. Further supporting evidence comes from the observation of the geographical differences of disease expression. In this setting, BS resembles rather a construction made of several dynamic and interactive LEGO pieces of different shapes and colors. These pieces presenting phenotypes with their own disease mechanism have presumably different genetic determinants. The analysis of phenotyping could help us to identify this disorder and hence could contribute to find better ways of treatment.

Does state ownership hurt or help minority shareholders? International evidence from control block acquisitions

Research SummaryWe argue that state ownership is a crucial policy instrument for alleviating what is perhaps the most important principal–principal (PP) agency problem around the globe: private benefits of control (PBC). Our results illustrate that states reduce PBC in the companies in which they acquire controlling ownership positions. We also examine how legal and political institutions influence the extent to which states accomplish this goal. Antiself‐dealing legal regulations make states more effective in their efforts to constrain PBC, while political constraints make them less effective. Regimes with high state capacity appear not to prioritize PBC reduction. We test and corroborate these ideas in a sample of 1,354 control transactions across 54 countries.Managerial SummaryThe one‐sided appropriation of wealth by dominant owners is arguably the biggest threat to minority shareholders around the globe. An important question that has thus far remained unaddressed is whether state ownership of firms increases or decreases the extraction of these so‐called PBC. By investigating a large number of transactions involving the transfer of corporate control in 54 countries, we find that state acquirers of controlling ownership positions generally respect minority shareholder rights more than other types of new controlling shareholders. This effect is stronger in countries with strong legal protection of minority shareholders. However, political constraints make it more challenging for state acquirers to keep PBC in check while “strong” states may (mis)use the firms they invest in as policy vehicles.